The Astrophysical Journal, 699:L102–L107, 2009 July 10 doi:10.1088/0004-637X/699/2/L102 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. DISCOVERY OF PULSATIONS FROM THE PULSAR J0205+6449 IN SNR 3C 58 WITH THE FERMI GAMMA-RAY SPACE TELESCOPE A. A. Abdo1,54, M. Ackermann2, M. Ajello2, W. B. Atwood3, M. Axelsson4,5, L. Baldini6, J. Ballet7, G. Barbiellini8,9, D. Bastieri10,11,B.M.Baughman12, K. Bechtol2, R. Bellazzini6, B. Berenji2, R. D. Blandford2, E. D. Bloom2, E. Bonamente13,14, A. W. Borgland2, A. Bouvier2, J. Bregeon6, A. Brez6, M. Brigida15,16, P. Bruel17,T.H.Burnett18, G. A. Caliandro15,16, R. A. Cameron2,F.Camilo19, P. A. Caraveo20, J. M. Casandjian7, C. Cecchi13,14, O.¨ Celik ¸ 21, A. Chekhtman22,1, C. C. Cheung21,J.Chiang2, S. Ciprini13,14, R. Claus2, I. Cognard23, J. Cohen-Tanugi24, J. Conrad4,25,26,55, C. D. Dermer1, A. de Angelis27, F. de Palma15,16,S.W.Digel2, M. Dormody3, E. do Couto e Silva2, P. S. Drell2, R. Dubois2, D. Dumora28,29, Y. Edmonds2, C. Espinoza30, C. Farnier24, C. Favuzzi15,16, W. B. Focke2, M. Frailis27, P. C. C. Freire31, Y. Fukazawa32,P.Fusco15,16, F. Gargano16, N. Gehrels21,33, S. Germani13,14, B. Giebels17, N. Giglietto15,16, F. Giordano15,16, T. Glanzman2, G. Godfrey2,I.A.Grenier7, M.-H. Grondin28,29, J. E. Grove1, L. Guillemot28,29, S. Guiriec34, Y. Hanabata32, A. K. Harding21, M. Hayashida2,E.Hays21, G. Hobbs35,R.E.Hughes12, G. Johannesson´ 2,A.S.Johnson2,R.P.Johnson3,T.J.Johnson21,33,W.N.Johnson1, S. Johnston35,T.Kamae2, V. M. Kaspi36, H. Katagiri32, J. Kataoka37, N. Kawai38,39, M. Keith35, M. Kerr18,J.Knodlseder¨ 40, M. Kramer30, F. Kuehn12,M.Kuss6, J. Lande2, L. Latronico6, M. Lemoine-Goumard28,29, M. Livingstone36,F.Longo8,9, F. Loparco15,16, B. Lott28,29, M. N. Lovellette1, P. Lubrano13,14,A.G.Lyne30, A. Makeev22,1, R. N. Manchester35, M. Marelli20, M. N. Mazziotta16,J.E.McEnery21, C. Meurer4,26,P.F.Michelson2, W. Mitthumsiri2, T. Mizuno32, A. A. Moiseev41,33, C. Monte15,16, M. E. Monzani2, A. Morselli42, I. V. Moskalenko2, S. Murgia2, P. L. Nolan2,E.Nuss24, T. Ohsugi32, N. Omodei6, E. Orlando43,J.F.Ormes44, D. Paneque2, J. H. Panetta2, D. Parent28,29, V. Pelassa24, M. Pepe13,14, M. Pesce-Rollins6, M. Pierbattista7, F. Piron24, T. A. Porter3,S.Raino` 15,16,R.Rando10,11,S.M.Ransom45, M. Razzano6,A.Reimer2,O.Reimer2, T. Reposeur28,29,S.Ritz21,33, L. S. Rochester2, A. Y. Rodriguez46,R.W.Romani2, F. Ryde4,25, H. F.-W. Sadrozinski3, D. Sanchez17, A. Sander12, P. M. Saz Parkinson3, C. Sgro` 6,E.J.Siskind47, D. A. Smith28,29,P.D.Smith12, G. Spandre6, P. Spinelli15,16, B. W. Stappers30, E. Striani42,48, M. S. Strickman1, D. J. Suson49,H.Tajima2, H. Takahashi32, T. Tanaka2, J. B. Thayer2, J. G. Thayer2, G. Theureau23, D. J. Thompson21, S. E. Thorsett3, L. Tibaldo10,11, D. F. Torres50,46, G. Tosti13,14, A. Tramacere51,2, Y. Uchiyama2,T.L.Usher2, A. Van Etten2, V. Vasileiou41,52, N. Vilchez40, V. Vitale42,48,A.P.Waite2,P.Wang2, K. Watters2, P. Weltevrede35, B. L. Winer12,K.S.Wood1,T.Ylinen53,4,25, and M. Ziegler3 1 Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA 2 W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305, USA 3 Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064, USA 4 The Oskar Klein Centre for Cosmo Particle Physics, AlbaNova, SE-106 91 Stockholm, Sweden 5 Department of Astronomy, Stockholm University, SE-106 91 Stockholm, Sweden 6 Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa, Italy 7 Laboratoire AIM, CEA-IRFU/CNRS/Universite´ Paris Diderot, Service d’Astrophysique, CEA Saclay, 91191 Gif sur Yvette, France 8 Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste, Italy 9 Dipartimento di Fisica, Universita` di Trieste, I-34127 Trieste, Italy 10 Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova, Italy 11 Dipartimento di Fisica “G. Galilei,” Universita` di Padova, I-35131 Padova, Italy 12 Department of Physics, Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210, USA 13 Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia, Italy 14 Dipartimento di Fisica, Universita` degli Studi di Perugia, I-06123 Perugia, Italy 15 Dipartimento di Fisica “M. Merlin” dell’Universita` e del Politecnico di Bari, I-70126 Bari, Italy 16 Istituto Nazionale di Fisica Nucleare, Sezione di Bari, 70126 Bari, Italy 17 Laboratoire Leprince-Ringuet, Ecole´ polytechnique, CNRS/IN2P3, Palaiseau, France 18 Department of Physics, University of Washington, Seattle, WA 98195-1560, USA 19 Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA 20 INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica, I-20133 Milano, Italy 21 NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 22 George Mason University, Fairfax, VA 22030, USA 23 Laboratoire de Physique et Chemie de l’Environnement, LPCE UMR 6115 CNRS, F-45071 Orleans´ Cedex 02, and Station de radioastronomie de Nan¸cay, Observatoire de Paris, CNRS/INSU, F-18330 Nan¸cay, France 24 Laboratoire de Physique Theorique´ et Astroparticules, Universite´ Montpellier 2, CNRS/IN2P3, Montpellier, France 25 Department of Physics, Royal Institute of Technology (KTH), AlbaNova, SE-106 91 Stockholm, Sweden 26 Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden 27 Dipartimento di Fisica, Universita` di Udine and Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Gruppo Collegato di Udine, I-33100 Udine, Italy 28 CNRS/IN2P3, Centre d’Etudes´ Nucleaires´ Bordeaux Gradignan, UMR 5797, Gradignan, 33175, France; [email protected] 29 Universite´ de Bordeaux, Centre d’Etudes´ Nucleaires´ Bordeaux Gradignan, UMR 5797, Gradignan, 33175, France 30 Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK 31 Arecibo Observatory, Arecibo, Puerto Rico 00612 32 Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan 33 University of Maryland, College Park, MD 20742, USA 34 University of Alabama in Huntsville, Huntsville, AL 35899, USA L102 No. 2, 2009 DISCOVERY OF PULSATIONS FROM PULSAR J0205+6449 IN SNR 3C 58 L103 35 Australia Telescope National Facility, CSIRO, Epping NSW 1710, Australia 36 Department of Physics, McGill University, Montreal, PQ, H3A 2T8, Canada 37 Waseda University, 1-104 Totsukamachi, Shinjuku-ku, Tokyo, 169-8050, Japan 38 Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198, Japan 39 Department of Physics, Tokyo Institute of Technology, Meguro City, Tokyo 152-8551, Japan 40 Centre d’Etude´ Spatiale des Rayonnements, CNRS/UPS, BP 44346, F-30128 Toulouse Cedex 4, France 41 Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA 42 Istituto Nazionale di Fisica Nucleare, Sezione di Roma “Tor Vergata,” I-00133 Roma, Italy 43 Max-Planck Institut fur¨ extraterrestrische Physik, 85748 Garching, Germany 44 Department of Physics and Astronomy, University of Denver, Denver, CO 80208, USA 45 National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903, USA 46 Institut de Ciencies de l’Espai (IEEC-CSIC), Campus UAB, 08193 Barcelona, Spain 47 NYCB Real-Time Computing Inc., Lattingtown, NY 11560-1025 48 Dipartimento di Fisica, Universita` di Roma “Tor Vergata,” I-00133 Roma, Italy 49 Department of Chemistry and Physics, Purdue University Calumet, Hammond, IN 46323-2094, USA 50 Institucio´ Catalana de Recerca i Estudis Avan¸cats (ICREA), Barcelona, Spain 51 Consorzio Interuniversitario per la Fisica Spaziale (CIFS), I-10133 Torino, Italy 52 University of Maryland, Baltimore County, Baltimore, MD 21250, USA 53 School of Pure and Applied Natural Sciences, University of Kalmar, SE-391 82 Kalmar, Sweden Received 2009 April 7; accepted 2009 June 5; published 2009 June 19 ABSTRACT We report the discovery of γ -ray pulsations (0.1 GeV) from the young radio and X-ray pulsar PSR J0205 + 6449 located in the Galactic supernova remnant 3C 58. Data in the γ -ray band were acquired by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope (formerly GLAST), while the radio rotational ephemeris used to fold γ -rays was obtained using both the Green Bank Telescope and the Lovell telescope at Jodrell Bank. The light curve consists of two peaks separated by 0.49 ± 0.01 ± 0.01 cycles which are aligned with the X-ray peaks. The first γ -ray peak trails the radio pulse by 0.08 ± 0.01 ± 0.01, while its amplitude decreases with increasing energy as for the other γ -ray pulsars. Spectral analysis of the pulsed γ -ray emission suggests a simple power law of index − ± ± +1.1 ± 2.1 0.1 0.2 with an exponential cutoff at 3.0−0.7 0.4 GeV. The first uncertainty is statistical and the second is systematic. The integral γ -ray photon flux above 0.1 GeV is (13.7 ± 1.4 ± 3.0) × 10−8 cm−2 s−1, which implies for a distance of 3.2 kpc and assuming a broad fan-like beam a luminosity of 8.3 × 1034 erg s−1 and an efficiency η of 0.3%. Finally, we report a 95% upper limit on the flux of 1.7 × 10−8 cm−2 s−1 for off-pulse emission from the object. Key words: pulsars: general – stars: neutron 1. INTRODUCTION X-ray pulse, showing that the first X-ray peak lags the radio pulse by φ = 0.10 ± 0.01.